1. Field of the Invention
The invention can be used for protecting working surfaces of parts of various plants, exposed to intensive wear by solids, gases and liquids. The present invention is particularly suited for protecting working surfaces of various parts of large-size blast furnace (5000 and 300 m.sup.3) charge conveyance system.
2. Description of the Prior Art
There are known large lining units composed of two steel sheets each 14 to 16 mm thick between which is placed a layer of a composite material, for example, one based on tungsten carbide, joined by diffusion to the above steel sheets.
However, characteristic of these lining units is a substantial specific consumption of rolled metal because of the need to retain the strength and the shape of the lining unit during the manufacture thereof, which includes a high-temperature heating. In addition, the costly composite material is utilized inefficiently in the known lining units because it is difficult to obtain a wear-resistant composite material layer of a thickness varying in accordance with the abradiung loads.
Another disadvantage of the above lining unit is its difficult manufacture, the process involving high consumptions of gas and electric power.
Also known is a lining unit composed of a metallic shell formed with a pipe of rectangular cross section filled with a wear-resistant material, for example, one based on tungsten carbide.
Although this design obviates some of the shortcomings inherent in the above-mentioned lining units, the use of a single type of rectangular cross section pipe provides no means for obtaining a lining unit having a variable-thickness wear-resistant layer to suit the conditions to which the unit is exposed in service.
Therefore, all the surfaces are protected on the assumption of maximum loads, thus leading to an inefficient consumption of the composite material.
It is therefore an object of the invention to provide a lining unit, so designed as to use efficiently the wear-resistant composite material.